Brake Light on Dash

[gabbyr100rs]

The brake light on my dash stays on intermittantly after I release the parking brake (I always use it, and it seems to hold). My brake function seems to be as good as ever. Sometimes the light goes days without staying on. It kind of fades out when it finally goes out.

Is my vacuum pump trying to tell me something after almost 150K??

Thanks for dispensing more of your collective knowledge and experience.

 

[f-two-fiddy]

Prolly need to replace that dash light bulb

 

[maxdiesel]

Prolly need to replace that dash light bulb

What would that have to do with the light intermitently staying on?

 

[Exekiel69]

I have the same issue a couple of weeks ago, I replaced the pump and now is as good as new. You can get the pump for $327 at the stealership, $169 autozone, $267 napa or go to fleabay and find a new one for $100 or less some times. I posted one yesterday that sold for $102, hope someone from this forum got it, it was a new motorcraft part.

 

[deanj]

Check the switch at the park brake. When you release the brake the plunger should be out, push it in and out a few times to make sure it is working.

 

[f-two-fiddy]

I agree to check the switch, also.
If the light bulb filiment is broken off one of it's posts, it'll bounce around and make contact itermittedly.

 

[gabbyr100rs]

Thanks, gents!

The light mostly goes out when I release my parking brake, although not always. This evening when I left the shop for home, it went out when I released the parking brake, then came back on and sort of faded out. Within a quarter of a mile or so, it had completely gone out and stayed that way until I put the parking brake back on in the driveway. The light always comes on when I set the parking brake.

I have checked the plunger on the parking brake switch, and it appears to be in the "out" position unless compressed by the released brake foot lever.

Somtimes the bulb acts like it has a mind of its own--if the vaccum level provided by the pump is no longer consistent, then if it were to fall below whatever the threshold is would that trigger the light back on?? That might explain why it "fades out" if the pump is able to finally produce the required vacuum level??

Thanks for the input!

 

[f-two-fiddy]

Do your brakes work properly while the light is acting up?

 

[NapaBavarian]

My '92 has that problem, I just use my foot to manually pull the pedal all the way back and it is OK, but it is my gas burning beater, so as long as it runs I don't throw $$$ at it

 

[Snowdiver]

I have a few rubber bands to hold the pedal out, I know but I'll never change.

 

[Rob94F250]

I have a similar problem on my '94 with similar mileage. The light would come on at the strangest times. It would sometimes fade out, other times it would go out "quite quickly".

I have flushed the entire brake system (including the RABS). I have also checked the relevant electrical connections. With the engine off, I verified that the brake booster was holding vacuum by pulling the check valve at the booster. I could also operate the A/C ducts by rotating the vent control knob (again with the engine off). This tells me that the check valves are OK, and that the systems downstream of the check valves aren't leaking. I don't notice any leaks between the pump and the check valves.

I was fortunate enough to inherit a new spare vacuum pump that the previous owner carried with him. I finally had a chance to swap it out tonight, so I will be able to confirm whether or not this was the problem when I drive her again tomorrow morning (it worked fine when I started her up in the garage tonight).

The one thing I did notice after swapping it out tonight is that there is a "strong" vacuum sound coming from the top inlet of the new pump. The old one never made a noticeable sound, which makes me think that it was "miled out".

 

[Agnem]

Welcome to the site Rob.

 

[gabbyr100rs]

Thanks for the replies. So far I have not noticed any diminished brake function with the "renegade" brake light on. The fact that it fades out, and the reply from Rob makes me think that it is on its last legs.

It is on the list to be replaced--will post results after I make the switch.

Thanks again for your collective help!

 

[MIDNIGHT RIDER]

My truck does the same thing.

Lift up on the park-brake cable and see if the light goes out.

If so, then you need to tighten the park-brake.

 

[MIDNIGHT RIDER]

Also, it is a five minute job to install a vacuum gauge.

Much cheaper than throwing dollars at a problem.